The present invention relates to a diaphragm drive mechanism for controlling the operation of a gas burner especially gas burners used in laboratories, such as Bunsen burners. More specifically, the invention relates to a diaphragm drive for the actuator of the main flame of a Bunsen burner for varying the size of the flame by remote control and to switch the flame on and off. Such an actuator mechanism comprises, for example, a valve disk cooperating with a valve seat and including a gasket as well as a valve spring and guiding means as well as throttling devices. Gas burners of the above type are simple in their structure and hence relatively inexpensive. Accordingly, such burners are frequently used in workshops, laboratories, and in many other fields. Further, such burners have normally, in addition to the main flame which may be switched on and off, a continuously burning small pilot light for igniting the main flame.
For certain jobs, the burning of the main flame is required only for a short period of time during which it is necessary to simultaneously perform other manual chores. Reference is made, as an example, to wax modeling, to the heating of instruments for their sterilization, and to externally exposing an apparatus to a flame treatment also for its sterilization. In connection with all these jobs, one achieves the following advantages in connection with a suitable remote control for the main flame which, for instance, may be actuated by a foot pedal. The gas consumption is reduced to the required quantity. The heating of the environment in which the burner is used is reduced, for example, in an apparatus, in a flue, or in an entire room. Thus, maintaining an agreeable room temperature is facilitated or air conditioning may be avoided altogether. Interfering turbulent air flows usually caused by unnececessary air heating are reduced. Avoiding or at least reducing turbulent air flows is advantageous in connection with laboratory work involving germs and in connection with work performed on so-called laminar flow benches.
Moreover, the remote control of the main flame, for example, by means of a foot pedal leaves both hands free for the actual job at hand.
Diamphragm drives cooperating with pressure transmitting fluidic media are known in connection with measuring devices, for example, manometers in which the diaphragm drive controls the operation of the pointer.
Further, diaphragm drives have been used for some time now in connection with air operated valves which are used in pipe conduits.
J. and R. Mueller describe in their book, "Adjustment Devices for Material Flows" (Stelleinrichtungen fuer Stoffstroeme) VEB-Verlag Technik, Berlin 1966, Page 65, such pneumatically operated valves which may be remotely controlled by air pressure, for example, for the purpose of controlling and regulating.
Gas burners, as they are used in laboratories and having a main flame which burns only during the time of actuation, are well known in the art. In such a burner, the main flame is, for example, switched on by applying pressure with the palm of the hand to a hand-operable plate. The flame is extinguished as soon as the plate is released. It is also known to keep the flame burning by rotating the plate into a locked position in which the operating plate is arrested for the duration during which the flame is supposed to burn. The operating plate is also known as a "wrist plate".
It is also known to equip gas burners for laboratories with a foot pedal control. These devices comprise an electromagnetic power unit which operates the actuator, or an electromagnetic valve is used instead of the electromagnetic power unit or in addition to such an actuator device.
It is frequently a hindrance if it is necessary to use a hand for the actuation of a gas burner because the operator needs his hands for other jobs. Thus, it is not unusual, that the gas burner is left burning with a large flame all the time, although it is not needed all the time.
The above mentioned use of diaphragm drives in connection with measuring devices serves primarily for the purpose of making a pressure or volume change visible by moving a pointer. Larger forces are not necessary for this purpose and would in fact impair the accuracy of the display. Thus, the diaphragm drives used in measuring devices are not suitable for driving an actuator. While it would be possible to drive a gas burner actuator with the membrane drive of a pneumatic valve, the structure of such pneumatic valve membrane drives is not suitable for gas burners because they are too large and bulky whereby the operation would be impaired.
An electromagnetic remote control of the main flame of a gas burner not only requires additional units in the remote control apparatus, such units in the form of solenoid magnets, are too large. Besides, such type of control requires an electrical supply and the required cables merely interfere with the proper use of the burner. Besides, an electrical connection constitutes an ignition source which should be avoided in connection with gas burners or with the gas supply conduit.